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Imagine you have recovered from a life-threatening lung cancer. The fear of a relapse would loom large over your head and you would stay as far away as possible from carcinogens like cigarettes. But not everybody thinks the same, according to a new study by American Cancer Society researchers, who report that nearly one in 10 cancer survivors smokes after years of diagnosis.

What’s more, the prevalence of smoking was more in people with bladder and lung cancers — conditions most likely to develop due to smoking. The study appears in the online journal Cancer Epidemiology, Biomarkers & Prevention and looks at rates of smoking in survivors of one of the 10 most common types of cancers.

Tobacco use during cancer therapy has been known to reduce the effectiveness of the treatment and increase the risk of complications. Patients who smoke have an increased risk of heart and lung complications during surgery. Radiation therapy also, to some extent, loses its effectiveness in smokers as compared to non-smokers. Both radiation and chemo are known to cause side effects like fatigue, weight loss, pneumonitis, and tissue damage in smokers.

Despite these well-known complications, previous studies have shown that a large number of cancer survivors don’t quit smoking even after diagnosis. But most of these studies have been conducted over a short period, and there is no sufficient information on smoking prevalence for survivors many years after diagnosis. This new study sought to answer that by conducting a survey among cancer survivors nine years after their initial diagnosis.

Led by Lee Westmaas, the study looked at survey responses from nearly 3,000 cancer survivors in the American Cancer Society's Study of Cancer Survivors–I (SCS-I), a longitudinal nationwide study of adult cancer survivors. The study was limited to the following types of cancers: breast, prostate, bladder, uterine, melanoma, colorectal, kidney, non-Hodgkin's lymphoma, ovarian, and lung. Of those interviewed, 9.3 percent of the survivors reported being current smokers, 41.2 percent were former smokers, and 49.6 percent were never smokers. Among current smokers, 83.1 percent smoked every day. Nearly half (46.6 percent) indicated they planned to quit, while 10.1 percent did not and 43.3 percent were not sure. Of the 1,209 former smokers, 88.6 percent had quit before their diagnosis.

According to the study, current smoking status depended more on the socioeconomic situation of the person. For example, younger female survivors who had lower education and lower income were most likely to remain smokers. A surprising finding was that married smokers were not highly motivated to quit, and intended to continue smoking.

"Effective cessation treatment for cancer survivors exists," wrote the authors in a press release, "but future population-based studies examining the importance of psychosocial variables, and their relationships to other health-related variables in predicting current smoking or motivation to quit, will further contribute to enhancing cessation strategies for all survivors who smoke."

The authors conclude that "Those who smoke heavily long after their diagnosis may require more intense treatment addressing specific psychosocial characteristics such as perceptions of risk, beliefs of fatalism, etc. that may influence motivation to quit."